Return rates: Palm Pre 11%. Apple iPhone 3GS 7%.

How often does the Palm PALM Pre break down and have to be returned and exchanged for a new one?

That question came up a few weeks after the Pre’s June 6 launch when Jesup and Lamont analyst Kevin Dede, citing a decidedly unscientific online survey, reported that the Pre’s return rate was a shocking 40%.

Pre Central, the site that conducted the poll, promptly disputed its own results. It ran a second, larger survey and got a slightly more comforting return rate: 18%.

A few days later, RBC Capital’s Mike Abramsky weighed in, estimating the actual return rate to be 2% – 3%, a figure he arrived at by throwing out from his estimate of the total return rate (8% to 15%) any units that were exchanged for new ones.

Now ChangeWave Research has released its own estimate, and while hardly definitive given the sample size, it at least provides some context.

Based on a survey of 198 Apple AAPL iPhone 3GS owners and 38 Pre owners, it found that the exchange rate of the Pre (11%) does indeed appear to be higher than the iPhone (7%), but not by much.